A two-dimensional Gabor filter passes specific orientations, frequencies, or components of an input signal. Such a Gabor filter is applied for image processing in the spatial domain for image enhancement, image restoration, texture analysis of an image, or image segmentation.
For example, U.S. Pat. No. 6,577,764 to Myler et al. is entitled “METHOD FOR MEASURING AND ANALYZING DIGITAL VIDEO QUALITY” and discloses measuring and analyzing the quality of video images by Gabor-filtering. U.S. Pat. No. 6,493,031 to Washizawa is entitled “VISUAL INFORMATION PROCESSING METHOD AND APPARATUS FOR EXTRACTING FEATURE QUANTITIES FROM A TWO-DIMENSIONAL IMAGE SIGNAL” and discloses characterizing 2-dimensional images by Gabor-filtering. Further, U.S. Pat. No. 6,546,155 to Krishnamachari is entitled “SYSTEM AND METHOD FOR ROTATION INVARIANT REPRESENTATION OF TEXTURE IN IMAGES” and discloses representing texture parameters that vary with rotation by Gabor-filtering.
Generally, a Gabor filter performs a convolution of an image with a Gabor mask function. Numerous calculations are performed for such a convolution, especially since the image is two-dimensional, and since the Gabor mask function has numerous parameters. Furthermore, the image may be organized into multiple regions, and a respective convolution is repeated for each of the multiple regions. Numerous calculations are performed for such repetition of convolutions.
However, a Gabor filter for performing numerous calculations is difficult to implement especially within an embedded system formed on a single silicon die.